Drill cuttings are produced in the process of drilling oil and gas wells. Drilling mud is circulated in the wellbore and carries drill cuttings produced by the drill bit from the bottom of the well to the well surface. The drilling mud with the drill cuttings are transferred to sieving devices (also known as shakers). The shakers separate the drill cuttings from the drilling mud. The drilling mud recovered from the shakers is then re-circulated to the well. The drill cuttings removed by the shaker may be delivered to other treatment devices such as a centrifugal dryer for further removal of drilling mud. The drill cuttings are then collected in tanks for temporary storage until further treatment or management.
The drill cuttings collected in tanks may be contaminated by residual drilling mud or other wellbore contaminants such as salts, hydrocarbons, and heavy metals. In order to reduce the volume of drill cuttings and make the drill cuttings more suitable for disposal, the drill cuttings may be treated by secondary separation (e.g., centrifugal cuttings dryers or drying shakers) or a solidification process. Solidification techniques stabilize, compact, or otherwise mechanically bind the drill cuttings into larger monolithic solids. Cement, fly ash, lime, and calcium oxide are often mixed with drill cuttings as additives in the solidification process. The surface area of drill cuttings is greatly decreased by the solidification process, resulting in reduced leaching of contaminants from the solidified drill cuttings.